Reviving a long-running controversy over antibacterial soaps and body wash, the U.S. Food and Drug Administration (FDA) announced on Monday that the makers of such products will have to prove that they are more effective than plain soap and water in preventing illness and curtailing infection.

According to the agency announcement, manufacturers will also need to prove that their products are safe for long-term use.

"Our goal is, if a company is making a claim that something is antibacterial and in this case promoting the concept that consumers who use these products can prevent the spread of germs, then there ought to be data behind that," said Sandra Kweder of the FDA's Center for Drug Evaluation and Research, in a statement. (See "Washing Hands in Hot Water Wastes Energy, Study Says.")

Alluding to the controversy around the most common active ingredients in thousands of antibacterial soap products—triclosan (liquid soaps) and triclocarban (bar soaps)—the FDA said, "Further, some data suggest that long-term exposure to certain active ingredients used in antibacterial products could pose health risks, such as bacterial resistance or hormonal effects."

The move comes more than a decade after antibacterial soaps were established on store shelves; one 2001 survey found 45 percent of soaps contained these antibacterial agents, which act to inhibit or kill off bacteria.

Now, with the call for data from manufacturers, disagreement over the safety of antimicrobial soaps has bubbled up into wide public view.

Safety Concerns

The FDA's recent announcement doesn't go far enough for some critics of triclosan, including Beyond Pesticides, a Washington, D.C.-based environmental and public health advocacy group. Nichelle Harriott, a staff scientist at Beyond Pesticides, told National Geographic that the FDA's announcement is "a good step forward" but that it lacks enough teeth.

For years, Beyond Pesticides has asked the FDA and the EPA to ban triclosan and the closely related triclocarban from consumer products, out of concern over their safety. In addition to soaps, triclosan and triclocarban also appear in a wide range of "antibacterial" items, from cosmetics to toothpaste, kitchen utensils, clothing, toys, and furniture.

Harriott said that, in her view, there are three main problems with triclosan and triclocarban: Studies suggest that they may be directly harmful, may lead to antibiotic resistance, and don't really work on the most important pathogens.

To the first point, Harriott said, "Triclosan is an endocrine disruptor, meaning it interferes with our hormone system, and in particular thyroid hormone." Since research to that effect is based on animal studies, she said the jury is still out on how seriously the chemicals might impact a human being over the course of their life, but she said there is enough data for concern.

She said animal studies have specifically linked triclosan to interfering with estrogen and pregnancy hormones, and noted that the scientists who conducted at least one of those studies warned that it could affect fetal development. In a study on sheep published in the November issue of the journal Environment International, researchers concluded that the "high potency of triclosan as an inhibitor of estrogen sulfotransferase activity raises concern about its possible effects on the ability of the placenta to supply estrogen to the fetus, and in turn on fetal growth and development."

"We don't want chemicals we use in cosmetics and soaps impacting the unborn," said Harriott.

FDA Response

The FDA wrote on an agency webpage that was updated last on December 16 that "triclosan is not currently known to be hazardous to humans." The agency acknowledged recent studies that call into question its safety, but noted that "effects in animals don't always predict effects in humans."

Still, the FDA wrote, "several scientific studies have come out since the last time FDA reviewed this ingredient that merit further review."

Harriott said that a study by the U.S. Centers for Disease Control and Prevention and published in Environmental Health Perspectivesfound traces of triclosan in urine in 75 percent of samples taken from 2,517 U.S. adults. Swedish and Australian studies also found it in umbilical cord blood and human breast milk, Harriott said, noting that the chemical is known for accumulating in fatty tissue.

What all that actually means in terms of people's health is still unclear, Harriott admitted, although she said it concerns her enough to want to see triclosan and triclocarban banned.

The Environment International study also noted that triclosan is increasingly found in the environment as a contaminant of sewage sludge and wastewater. That's one of the reasons why the agency Health Canada asked companies to voluntarily phase the chemical out of use above the border in 2012.

In support of that request, Environment Defense Canada told Health Canada, "Canadians should not be brushing their teeth and washing their dishes with a cancer-causing chemical."

In defense of the agent, the American Cleaning Institute says on its website that "triclosan has been used safely in personal care products for more than 30 years."

Leading to Superbugs?

Harriott said there have also been studies showing that bacteria have become resistant to triclosan in the lab. "Those strains that became resistant to triclosan are also resistant to antibiotics, and it's a major concern when you talk about the efficacy of antibiotics in a medical setting," she said.

Harriott said it's unclear if such triclosan-resistant bacteria are currently living in the real world, outside laboratories, but she said she thinks it is likely.

Striking a blow at their effectiveness in the first place, Harriott also said of triclosan and triclocarban that "they get rid of germs, but they don't get rid of the organisms of public health interest, like E. coli and staph. They have no effect on those."

Washing Alternatives

For all those reasons, Harriott says she tells people to stick with what they know is safe: plain old soap and water. "I understand people are concerned about germs, but regular soap and water works just as fine as antibacterial soaps," she said.

If people don't have access to those, the next-best thing would be alcohol-based sanitizers, she said.

"Anything beyond regular soap and water and sanitizers is just not necessary," she said.